U.S. patent number 10,105,697 [Application Number 14/826,716] was granted by the patent office on 2018-10-23 for methods, systems, and computer program products for detecting a surface using a pipette and/or positioning a pipette.
This patent grant is currently assigned to bioMerieux, Inc.. The grantee listed for this patent is bioMerieux, Inc.. Invention is credited to Joel Patrick Harrison, Daniel Oliver Luebbert, Daniel Joseph Pingel, Jeremey Joseph Pionke.
United States Patent |
10,105,697 |
Pingel , et al. |
October 23, 2018 |
**Please see images for:
( Certificate of Correction ) ** |
Methods, systems, and computer program products for detecting a
surface using a pipette and/or positioning a pipette
Abstract
This invention relates to methods, systems, and computer program
products for detecting a surface using a pipette and/or for
positioning a pipette.
Inventors: |
Pingel; Daniel Joseph (St.
Peters, MO), Luebbert; Daniel Oliver (St. Peters, MO),
Harrison; Joel Patrick (Maryville, IL), Pionke; Jeremey
Joseph (O'Fallon, MO) |
Applicant: |
Name |
City |
State |
Country |
Type |
bioMerieux, Inc. |
Durham |
NC |
US |
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Assignee: |
bioMerieux, Inc. (Durham,
NC)
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Family
ID: |
53901190 |
Appl.
No.: |
14/826,716 |
Filed: |
August 14, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160047835 A1 |
Feb 18, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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62037650 |
Aug 15, 2014 |
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62037652 |
Aug 15, 2014 |
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62037659 |
Aug 15, 2014 |
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62037661 |
Aug 15, 2014 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L
3/0275 (20130101); G01N 35/00623 (20130101); B01L
3/021 (20130101); B01L 3/0237 (20130101); G01N
35/0099 (20130101); G01N 35/1009 (20130101); G01N
35/10 (20130101); B01L 2300/0627 (20130101); B01L
3/0268 (20130101); G01N 2035/103 (20130101); B01L
2400/02 (20130101); G01N 2035/1018 (20130101); B01L
2300/0681 (20130101); B01L 2200/146 (20130101) |
Current International
Class: |
G01N
35/10 (20060101); G01N 35/00 (20060101); B01L
3/02 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2 561 929 |
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Feb 2013 |
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EP |
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WO 2012/045416 |
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Apr 2012 |
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WO |
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WO 2012/069925 |
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May 2012 |
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WO |
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Other References
International Search Report and the Written Opinion of the
International Searching Authority corresponding to International
Patent Application No. PCT/US2015/045276 (19 pages) (dated Jan. 25,
2016). cited by applicant .
U.S. Appl. No. 14/826,736, Luebbert et al., filed Aug. 14, 2015.
cited by applicant .
U.S. Appl. No. 14/826,749, Pionke et al., filed Aug. 14, 2015.
cited by applicant .
U.S. Appl. No. 14/826,767, Luebbert et al., filed Aug. 14, 2015.
cited by applicant .
PREVI.RTM. Isola Product Overview www.biomerieux-usa.com (2 pages)
(2009). cited by applicant .
"Tecan's Pressure Monitored Pipetting supports Swiss BioQuant's
dedication to excellence" www.tecan.com (1 page) (Oct. 25, 2011).
cited by applicant.
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Primary Examiner: West; Paul
Attorney, Agent or Firm: Myers Bigel, P.A.
Parent Case Text
RELATED APPLICATION INFORMATION
This application claims the benefit of and priority to U.S.
Provisional Application Ser. No. 62/037,650, filed Aug. 15, 2014,
U.S. Provisional Application Ser. No. 62/037,652, filed Aug. 15,
2014, U.S. Provisional Application Ser. No. 62/037,659, filed Aug.
15, 2014, and U.S. Provisional Application Ser. No. 62/037,661,
filed Aug. 15, 2014, the disclosures of which are hereby
incorporated by reference herein in their entirety.
Claims
What is claimed is:
1. A method comprising: measuring a pipette pressure at an internal
portion of a pipette to generate a plurality of pipette pressure
values; determining a pressure difference relative to at least one
previously measured pipette pressure value; estimating a rate of
change in pipette pressure, wherein estimating the rate of change
in pipette pressure comprises weighting the pressure difference to
provide a weighted pressure difference; estimating at least one
statistical variable corresponding to the rate of change in pipette
pressure; comparing the at least one statistical variable to at
least one pipette pressure related threshold; and responsive to
comparing the at least one statistical variable to the at least one
pipette pressure related threshold, estimating a pipette
position.
2. The method of claim 1, wherein estimating the rate of change in
pipette pressure comprises summing the weighted pressure difference
with at least one weighted previously calculated rate of change in
pipette pressure.
3. The method of claim 1, wherein measuring the pipette pressure
comprises measuring the pipette pressure with a liquid and/or gas
in a pipette tip attached to the pipette.
4. The method of claim 1, wherein measuring the pipette pressure
comprises measuring the pipette pressure while aspirating gas into
a pipette tip attached to the pipette and while the pipette is
moving toward a surface and/or the surface is moving toward the
pipette.
5. The method of claim 4, wherein the pipette aspirates gas at a
constant flow rate.
6. The method of claim 1, wherein estimating the at least one
statistical variable comprises estimating an average rate of change
in pipette pressure.
7. The method of claim 1, wherein estimating the at least one
statistical variable comprises estimating a ratio relating to the
rate of change in pipette pressure.
8. The method of claim 7, wherein the ratio relating to the rate of
change in pipette pressure includes the rate of change in pipette
pressure and the average rate of change in pipette pressure.
9. The method of claim 1, wherein comparing the at least one
statistical variable comprises comparing the rate of change in
pipette pressure to a first pressure related threshold and
comparing the at least one statistical variable to a second
pressure related threshold.
10. The method of claim 9, wherein the at least one statistical
variable is a ratio of the rate of change in pipette pressure
divided by an average rate of change in pipette pressure, wherein
the first pressure related threshold is a rate of change in pipette
pressure threshold and the second pressure related threshold is a
pipette pressure ratio threshold, and wherein contact with a
surface is detected when the rate of change in pipette pressure is
less than or equal to the rate of change in pipette pressure
threshold and the ratio of the rate change in pipette pressure
divided by the average rate of change in pipette pressure is
greater than or equal to the pipette pressure ratio threshold.
11. The method of claim 1, wherein estimating the pipette position
comprises estimating the position of a pipette tip relative to a
surface.
12. The method of claim 1, wherein estimating the pipette position
comprises determining that a surface is not in contact with the
pipette and, responsive to determining that the surface is not in
contact with the pipette, continuing to estimate the pipette
position.
13. The method of claim 1, wherein estimating the pipette position
comprises determining that a surface is in contact with the
pipette.
14. The method of claim 13, wherein determining that the surface is
in contact with the pipette comprises determining if the distal
orifice of a pipette tip attached to the pipette has sealed with
the surface.
15. The method of claim 13, wherein determining that the surface is
in contact with the pipette comprises detecting at least two
consecutive data points that indicate contact to the surface with
the pipette.
16. The method of claim 13, further comprising, responsive to
determining that the surface is in contact with the pipette,
stopping movement of the pipette toward the surface and adjusting
the pipette to a position above the surface, or responsive to
determining that the surface is in contact with the pipette,
stopping movement of the surface toward the pipette and adjusting
the surface to a position below the pipette.
17. The method of claim 1, further comprising detecting a
positioning error, wherein detecting the positioning error
comprises comparing the rate of change in pipette pressure to at
least one pressure error threshold.
18. The method of claim 1, wherein estimating the rate of change in
pipette pressure comprises mathematically weighting the pressure
difference to provide the weighted pressure difference.
19. The method of claim 1, wherein a pipette pressure value in the
plurality of pipette pressure values comprises an analog
signal.
20. The method of claim 1, wherein a pipette pressure value in the
plurality of pipette pressure values comprises a digital
signal.
21. A computer system, comprising: a processor; and a memory
coupled to the processor, the memory comprising computer readable
program code embodied therein that, when executed by the processor,
causes the processor to perform any of the operations of the method
of claim 1.
22. A computer program product comprising: a non-transitory
computer readable storage medium having computer readable code
embodied in the medium, the computer code comprising: computer
readable code to perform operations of the method of claim 1.
Description
FIELD OF THE INVENTION
This invention relates to methods, systems, and computer program
products, particularly to methods, systems, and computer program
products for detecting a surface using a pipette and/or for
positioning a pipette.
BACKGROUND
The isolation of individual colonies of micro-organisms,
particularly bacteria, is an important procedure in microbiological
laboratories. Traditionally, the isolation of bacteria has been
performed manually by skilled laboratory technicians who first
dispense a microbiological sample onto the surface of a solid
growth culture medium, such as agar in a Petri dish, followed by
the use of a hand-tool to spread the sample across the surface of
the medium, known as "streaking". However, these laboratory
procedures can also be automated.
For both traditional, manual laboratory procedures and automated
laboratory procedures, monitoring and/or verifying that a sample
volume has been correctly dispensed onto a solid growth culture
medium can be important. This is because if a sample has not been
correctly dispensed, then it can create the risk of a false
negative.
BRIEF SUMMARY
It is noted that aspects described with respect to one embodiment
may be incorporated in different embodiments although not
specifically described relative thereto. That is, all embodiments
and/or features of any embodiments can be combined in any way
and/or combination. Moreover, other systems, articles of
manufacture, methods, and/or computer program products according to
embodiments will be or become apparent to one with skill in the art
upon review of the following drawings and detailed description. It
is intended that all such additional systems, articles of
manufacture, methods, and/or computer program products be included
within this description, be within the scope of the present
inventive concept, and be protected by the accompanying claims.
Some embodiments are directed to systems, articles of manufacture,
methods and/or computer program products for positioning a pipette
and/or detecting a surface using a pipette. In some embodiments,
operations include positioning a pipette at a first distance above
a surface using a first position detector and positioning the
pipette at a second distance above the surface using a second
position detector that is different from the first position
detector, wherein the second distance is less than the first
distance. In some embodiments, the second position detector
includes a pipette pressure detector and the first position
detector uses a metric other than pressure. Some embodiments
include, prior to positioning the pipette at the second distance,
contacting the surface with a tip of the pipette.
In some embodiments, operations include measuring a pipette
pressure at an internal portion of a pipette to generate a
plurality of pipette pressure values. Some embodiments include
determining a pressure difference relative to at least one
previously measured pipette pressure value. Some embodiments
include estimating at least one statistical variable corresponding
to a rate of change in pipette pressure. In some embodiments, the
at least one statistical variable is compared to at least one
pipette pressure related threshold. Some embodiments include,
responsive to comparing the at least one statistical variable to
the at least one pipette pressure related threshold, estimating a
pipette position. Some embodiments include, responsive to comparing
the at least one statistical variable to the at least one pressure
related threshold, determining if the surface has been contacted
with the pipette tip.
In some embodiments, measuring the pipette pressure includes
measuring the pipette pressure with a liquid and/or gas in a
pipette tip attached to the pipette. In some embodiments, measuring
the pipette pressure includes measuring the pipette pressure at
given time intervals. Some embodiments include measuring the
pipette pressure while aspirating gas into a pipette tip attached
to the pipette and while the pipette is moving toward a surface
and/or the surface is/are moving toward the pipette. In some
embodiments, the pipette is moving downward in a z-direction toward
the surface. Some embodiments include the pipette aspirating gas at
a constant flow rate.
Some embodiments include, prior to estimating the at least one
statistical variable, estimating the rate of change in pipette
pressure. In some embodiments, estimating the rate of change in
pipette pressure includes mathematically weighting the pressure
difference to provide a weighted pressure difference. In some
embodiments, estimating the rate of change in pipette pressure
includes summing the weighted pressure difference with at least one
weighted previously calculated rate of change in pipette pressure.
In some embodiments, the pressure difference is weighted by about
0% to 49% and the previously calculated rate of change in pipette
pressure is weighted by about 51% to about 100%.
In some embodiments, estimating the at least one statistical
variable includes estimating an average rate of change in pipette
pressure. In some embodiments, estimating the at least one
statistical variable includes estimating a ratio relating to the
rate of change in pipette pressure. In some embodiments, the ratio
relating to the rate of change in pipette pressure includes the
rate of change in pipette pressure and the average rate of change
in pipette pressure.
In some embodiments, comparing the at least one statistical
variable includes comparing the rate of change in pipette pressure
to a first pressure related threshold and comparing a statistical
variable to a second pressure related threshold. In some
embodiments, the at least one pressure related threshold is
determined using a given rate of aspiration and/or a given rate of
movement. In some embodiments, the statistical variable is a ratio
of the rate of change in pipette pressure divided by an average
rate of change in pipette pressure. In some embodiments, the first
pressure related threshold is a rate of change in pipette pressure
threshold and the second pressure related threshold is a pipette
pressure ratio threshold. Some embodiments include detecting
contact with a surface detected when the rate of change in pipette
pressure is less than or equal to the rate of change in pipette
pressure threshold and the ratio of the rate change in pipette
pressure divided by the average rate of change in pipette pressure
is greater than or equal to the pipette pressure ratio
threshold.
In some embodiments, estimating the pipette position includes
estimating the position of a pipette tip relative to a surface. In
some embodiments, estimating the pipette position includes
determining that a surface is not in contact with the pipette and,
responsive to determining that the surface is not in contact with
the pipette, continuing to estimate the pipette position. In some
embodiments, estimating the pipette position includes determining
that a surface is in contact with the pipette. In some embodiments,
determining if the surface has been contacted with the pipette tip
includes estimating the position of the pipette tip relative to the
surface.
Some embodiments include determining that the surface is in contact
with the pipette by determining that the distal orifice of a
pipette tip attached to the pipette has sealed with the surface. In
some embodiments, determining that the surface is in contact with
the pipette includes detecting at least two consecutive data points
that indicate contact to the surface with the pipette.
Some embodiments include, responsive to determining that the
surface is in contact with the pipette, stopping movement of the
pipette toward the surface and adjusting the pipette to a position
above the surface. In some embodiments, responsive to determining
that the surface is in contact with the pipette, stopping movement
of the surface toward the pipette and adjusting the surface to a
position below the pipette. Some embodiments include, responsive to
determining that the surface is in contact with the pipette,
stopping the aspiration of gas.
In some embodiments, operations include aspirating a liquid into
the pipette tip and positioning the pipette tip at a first distance
above a surface. Some embodiments include moving the pipette toward
the surface while aspirating gas into the pipette tip. Some
embodiments include measuring pipette pressure at an internal
portion of the pipette and collecting pipette pressure data. In
some embodiments, measuring pipette pressure at an internal portion
of the pipette includes generating a plurality of pipette pressure
values. In some embodiments, the pipette pressure data includes the
plurality of pipette pressure values. In some embodiments, contact
to the surface with the pipette tip is detected using the pipette
pressure data.
Some embodiments are directed to systems, articles of manufacture,
methods and/or computer program products for verifying dispensing
of a fluid from a pipette. In some embodiments, operations include
collecting pressure data while dispensing fluid from a pipette tip
attached to a pipette. In some embodiments, the pressure data
includes a plurality of pressure values measured at an internal
portion of the pipette and taken over a given time interval. In
some embodiments, the plurality of pressure values includes a
maximum pressure value and a minimum pressure value. Some
embodiments include estimating a pressure range value between the
maximum pressure value and the minimum pressure value. Some
embodiments include determining that the fluid included a liquid,
responsive to the pressure range value being greater than or equal
to at least one threshold. Some embodiments include determining
that the fluid did not include a liquid, responsive to the pressure
range value being less than the at least one threshold.
In some embodiments, collecting pressure data while dispensing
fluid from the pipette tip attached to the pipette includes
measuring pipette pressure at given sampling time intervals. Some
embodiments include dispensing fluid from the pipette tip attached
to the pipette over the given time interval.
In some embodiments, collecting pressure data while dispensing
fluid from the pipette tip attached to the pipette includes
dispensing the fluid at a given rate. In some embodiments, the
given rate is in a range of about 5 .mu.L/sec to about 400
.mu.L/sec.
Some embodiments include, prior to collecting pressure data while
dispensing fluid from the pipette tip attached to the pipette,
aspirating a gas into the pipette tip and subsequently aspirating a
liquid into the pipette tip. In some embodiments, prior to
collecting pressure data while dispensing fluid from the pipette
tip attached to the pipette, at least a portion of the liquid is
dispensed from the pipette tip.
In some embodiments, collecting pressure data while dispensing
fluid from the pipette tip attached to the pipette includes
dispensing all fluid present in the pipette tip in the given time
interval.
In some embodiments, estimating the pressure range value between
the maximum pressure value and the minimum pressure value includes
subtracting the minimum pressure value from the maximum pressure
value to obtain the pressure range value.
Some embodiments include prior to estimating the pressure range
value between the maximum pressure value and the minimum pressure
value, removing a portion of pressure values from the plurality of
pressure values. In some embodiments, the portion of pressure
values is a given number of consecutive pressure values. In some
embodiments, the portion of pressure values includes the initial
pressure value in the plurality of pressure values.
In some embodiments, determining that the fluid did not include a
liquid indicates that a dispensing error occurred.
Some embodiments include estimating a pressure area ratio that
identifies at least two pressure data curves, each of the at least
two pressure data curves corresponding to at least a portion of the
plurality of pressure values. In some embodiments, the pressure
area ratio is compared to at least one threshold. Some embodiments
include determining that the fluid included a sufficient amount of
the liquid, responsive to the pressure area ratio being greater
than at least one threshold. Some embodiments include determining
that the fluid did not include a sufficient amount of the liquid,
responsive to the pressure area ratio being less than or equal to
at least one threshold.
In some embodiments, estimating the pressure area ratio includes
estimating a maximum area corresponding to a pressure data curve
that corresponds to the maximum pressure value and the minimum
pressure value. In some embodiments, estimating the pressure area
ratio includes estimating an actual pressure area corresponding to
a pressure data curve that corresponds to the plurality of pressure
values. Some embodiments include multiplying the pressure range
value by the given time interval to estimate the maximum area. In
some embodiments, the given time interval is the number of pressure
values in the plurality of pressure values multiplied by the given
sampling time interval between consecutive pressure values in the
plurality of pressure values.
In some embodiments, estimating the actual pressure area includes
summing areas of a plurality of rectangles. In some embodiments, a
width of each rectangle of the plurality of rectangles is the given
sampling time interval between consecutive pressure values in the
plurality of pressure values. In some embodiments, a height of each
rectangle of the plurality of rectangles is a midpoint between at
least two consecutive pressure values minus the minimum pressure
value.
In some embodiments, determining that the fluid did not include a
sufficient amount of the liquid indicates that a dispensing error
occurred.
Some embodiments are directed to systems, articles of manufacture,
methods and/or computer program products for detecting pipette tip
integrity. In some embodiments, operations include collecting
pressure data while aspirating a gas into a pipette tip attached to
a pipette. In some embodiments, the pipette tip includes a filter.
In some embodiments, the pressure data includes a plurality of
pressure values measured at an internal portion of the pipette and
taken over a given time interval. In some embodiments, the
plurality of pressure values include a maximum pressure value and a
minimum pressure value.
Some embodiments include estimating a pressure range value between
the maximum pressure value and the minimum pressure value. In some
embodiments, responsive to the pressure range value being greater
than or equal to a lower threshold and the pressure range value
being less than or equal to an upper threshold, it is determined
that the pipette tip attached to the pipette is properly
functioning. Some embodiments include, responsive to the pressure
range value being less than a lower threshold. In some embodiments,
responsive to the pressure range value being greater than an upper
threshold, it is determined that the pipette tip attached to the
pipette is not properly functioning.
In some embodiments, collecting pressure data while aspirating gas
into the pipette tip attached to the pipette includes measuring
pipette pressure at given time intervals. Some embodiments include
aspirating gas into the pipette tip attached to the pipette over a
given time interval.
In some embodiments, collecting pressure data while aspirating gas
into the pipette tip attached to the pipette includes aspirating
the gas at a given rate of aspiration. Some embodiments include
aspirating gas a rate of aspiration in a range of about 300 .mu.L/s
to about 700 .mu.L/s.
In some embodiments, collecting pressure data while aspirating gas
into the pipette tip attached to the pipette includes aspirating
gas into the pipette tip prior to aspirating a liquid into the
pipette tip. Some embodiments include collecting pressure data
while aspirating a given volume of gas into the pipette tip
attached to the pipette.
In some embodiments, estimating the pressure range value between
the maximum pressure value and the minimum pressure value includes
subtracting the minimum pressure value from the maximum pressure
value to obtain the pressure range value.
Some embodiments include that the upper threshold and/or the lower
threshold is/are determined using a given rate of aspiration. In
some embodiments, the given rate of aspiration is in a range of
about 300 .mu.L/sec to about 700 .mu.L/sec. Some embodiments
include that the given rate of aspiration is the same as the rate
of aspiration for aspirating the gas into the pipette tip attached
to the pipette.
Some embodiments include, responsive to the pressure range value
being greater than or equal to the lower threshold and the pressure
range value being less than or equal to the upper threshold,
determining that the pipette tip attached to the pipette is
suitable for use.
Some embodiments include, responsive to the pressure range value
being greater than or equal to the lower threshold and the pressure
range value being less than or equal to the upper threshold,
aspirating a liquid into the pipette tip.
Some embodiments include, responsive to the pressure range value
being less than the lower threshold or the pressure range value
being greater than the upper threshold, removing the pipette tip
from the pipette.
Some embodiments include, responsive to the pressure range value
being less than the lower threshold or the pressure range value
being greater than the upper threshold, determining that the
pipette tip is defective, clogged, and/or improperly attached to
the pipette.
Some embodiments include, detecting that the pipette tip is
defective or without a filter responsive to the pressure range
value being less than the lower threshold.
Some embodiments include, detecting that the pipette tip is
defective responsive to the pressure range value being greater than
the upper threshold. In some embodiments, the pipette tip is a
clogged.
In some embodiments, the maximum pressure value is measured at a
first point in time and the minimum pressure value is measured at a
second point in time and the first point in time is before the
second point in time. In some embodiments, the maximum pressure
value is measured at a first point in time and the minimum pressure
value is measured at a second point in time and the second point in
time is before the first point in time.
Some embodiments are directed to systems, articles of manufacture,
methods and/or computer program products for detecting a droplet.
In some embodiments, operations include estimating a plurality of
rate of change in pipette pressure values during a given time
interval. Some embodiments include detecting the formation of a
droplet at a distal end of a pipette tip attached to a pipette,
responsive to at least one of the plurality of rate of change in
pipette pressure values being greater than or equal to an upper
pressure related threshold and at least one of the plurality of
rate of change in pipette pressure values being less than or equal
to a lower pressure related threshold.
In some embodiments, estimating the plurality of rate of change in
pipette pressure values during the given time interval includes
measuring a pipette pressure at an internal portion of a pipette at
given sampling time intervals to generate a plurality of pipette
pressure values. In some embodiments, estimating the plurality of
rate of change in pipette pressure values during the given time
interval includes determining a plurality of pressure differences
relative to at least one previously measured pipette pressure
value. In some embodiments, estimating the plurality of rate of
change in pipette pressure values during the given time interval
includes mathematically weighting each of the plurality of pressure
differences to provide the plurality of rate of change in pipette
pressure values.
In some embodiments, mathematically weighting each of the plurality
of pressure differences to provide the plurality of rate of change
in pipette pressure values includes weighting a most recently
determined pressure difference to provide a weighted pressure
difference. In some embodiments, mathematically weighting each of
the plurality of pressure differences to provide the plurality of
rate of change in pipette pressure values includes weighting at
least one previously calculated rate of change in pipette pressure
value to provide a weighted previously calculated rate of change in
pipette pressure value. Some embodiments include summing the
weighted pressure difference and the weighted previously calculated
rate of change in pipette pressure value. In some embodiments, the
most recently determined pressure difference is weighted by about
0% to 49% and the at least one previously calculated rate of change
in pipette pressure value is weighted by about 51% to about
100%.
In some embodiments, the plurality of rate of change in pipette
pressure values changes over a period of time.
Some embodiments include determining the upper pressure related
threshold and/or the lower pressure related threshold using a given
rate of dispense.
In some embodiments, the droplet has a volume in a range of about
0.5 .mu.L to about 3.5 .mu.L.
In some embodiments, at least one of the plurality of rate of
change in pipette pressure values corresponds to a rate of change
in pipette pressure while the pipette is dispensing a gas. In some
embodiments, at least one of the plurality of rate of change in
pipette pressure values corresponds to a rate of change in pipette
pressure while the pipette is dispensing a liquid.
Some embodiments include, responsive to detecting the formation of
the droplet, stopping dispensing of liquid from the pipette
tip.
In some embodiments, a clog is detected in the pipette tip attached
to the pipette. In some embodiments, detecting the clog in the
pipette tip attached to the pipette includes determining that a
given number of rate of change in pipette pressure values of the
plurality of rate of change in pipette pressure values are greater
than or equal to a first clog related threshold. In some
embodiments, detecting the clog in the pipette tip attached to the
pipette includes determining that an updated pressure difference
corresponding to a most recently measured pipette pressure value of
the plurality of pipette pressure values is greater than a second
clog related threshold.
In some embodiments, the given number of rate of change in pipette
pressure values of the plurality of rate of change in pipette
pressure values corresponds to a given period of time.
Some embodiments include estimating the updated pressure
difference. In some embodiments, estimating the updated pressure
difference includes selecting a minimum pipette pressure value from
the plurality of pipette pressure values and subtracting the
minimum pipette pressure value from the most recently measured
pipette pressure value of the plurality of pipette pressure
values.
In some embodiments, the second clog related threshold corresponds
to a cumulative rise in pressure of a given value. Some embodiments
include determining the first clog related threshold and/or the
second clog related threshold using a given rate of dispense.
Some embodiments include detecting that the pipette tip does not
contain a liquid. In some embodiments, detecting that the pipette
tip does not contain the liquid includes estimating a plurality of
changes in pressure over a given period of time. In some
embodiments, detecting that the pipette tip does not contain the
liquid further includes determining that a portion of the plurality
of changes in pressure indicate no significant change in pressure.
In some embodiments, the portion of the plurality of changes in
pressure that indicates no significant change in pressure is at
least 50%.
In some embodiments, estimating the plurality of changes in
pressure over the given period of time includes measuring the
pipette pressure at an initial point in time and estimating the
plurality of changes in pressure at a given point in time after the
initial point in time.
Some embodiments include measuring a pipette pressure at an
internal portion of the pipette including a pipette tip attached
thereto to generate a plurality of pipette pressure values. In some
embodiments, a pressure difference relative to at least one
previously measured pipette pressure value is determined. Some
embodiments include providing a plurality of pressure difference
values. In some embodiments, a portion of the plurality of pressure
difference values is compared with an upper pressure related
threshold and a lower pressure related threshold. Some embodiments
include detecting the formation of a droplet, responsive to
determining that at least one pressure difference value of the
portion of the plurality of pressure difference values is greater
than or equal to the upper pressure related threshold and that at
least one pressure difference value of the portion of the plurality
of pressure difference values is less than or equal to the lower
pressure related threshold.
In some embodiments, comparing the portion of the plurality of
pressure difference values with the upper pressure related
threshold and the lower pressure related threshold includes
comparing a portion of a plurality of rate of change in pipette
pressure values with the upper pressure related threshold and the
lower pressure related threshold.
Some embodiments include estimating a rate of change in pipette
pressure and providing a plurality of rate of change in pipette
pressure values. In some embodiments, estimating the rate of change
in pipette pressure includes mathematically weighting the pressure
difference to provide a weighted pressure difference. In some
embodiments, estimating the rate of change in pipette pressure
includes summing the weighted pressure difference with at least one
weighted previously calculated rate of change in pipette pressure.
In some embodiments, the pressure difference is weighted by about
0% to 49% and the previously calculated rate of change in pipette
pressure is weighted by about 51% to about 100%.
Some embodiments include measuring the pipette pressure at given
sampling time intervals. In some embodiments, measuring the pipette
pressure includes measuring the pipette pressure while the pipette
is positioned at a given position.
In some embodiments, comparing the portion of the plurality of
pressure difference values with the upper pressure related
threshold and the lower pressure related threshold includes
comparing at least two pressure difference values.
In some embodiments, the plurality of pressure difference values
changes over a period of time.
Some embodiments include determining the upper pressure related
threshold and/or the lower pressure related threshold using a given
rate of dispense.
In some embodiments, the droplet has a volume in a range of about
0.5 .mu.L to about 3.5 .mu.L.
In some embodiments, at least one pressure difference value of the
portion of the plurality of pressure difference values corresponds
to a pipette pressure while the pipette is dispensing a gas. In
some embodiments, at least one pressure difference value of the
portion of the plurality of pressure difference values corresponds
to a pipette pressure while the pipette is dispensing a liquid.
Some embodiments include, responsive to detecting the formation of
the droplet, stopping dispensing of liquid from the pipette
tip.
Some embodiments include detecting a clog in the pipette tip
attached to the pipette. In some embodiments, detecting the clog in
the pipette tip attached to the pipette includes determining that a
given number of rate of change in pipette pressure values of the
plurality of rate of change in pipette pressure values are greater
than or equal to a first clog related threshold. In some
embodiments, detecting the clog in the pipette tip attached to the
pipette includes determining that an updated pressure difference
corresponding to a most recently measured pipette pressure value of
the plurality of pipette pressure values is greater than a second
clog related threshold.
In some embodiments, the given number of rate of change in pipette
pressure values of the plurality of rate of change in pipette
pressure values corresponds to a given period of time.
Some embodiments include estimating the updated pressure
difference. In some embodiments, estimating the updated pressure
difference includes selecting a minimum pipette pressure value from
the plurality of pipette pressure values and subtracting the
minimum pipette pressure value from the most recently measured
pipette pressure value of the plurality of pipette pressure
values.
In some embodiments, the second clog related threshold corresponds
to a cumulative rise in pressure of a given value. In some
embodiments, the first clog related threshold and/or the second
clog related threshold is/are determined using a given rate of
dispense.
Some embodiments include detecting that the pipette tip does not
contain a liquid. In some embodiments, detecting that the pipette
tip does not contain a liquid includes estimating a plurality of
changes in pressure over a given period of time. In some
embodiments, detecting that the pipette tip does not contain the
liquid includes determining that a portion of the plurality of
changes in pressure indicate no significant change in pressure. In
some embodiments, the portion of the plurality of changes in
pressure that indicates no significant change in pressure is at
least 50%.
In some embodiments, estimating the plurality of changes in
pressure over the given period of time includes measuring the
pipette pressure at an initial point in time and estimating the
plurality of changes in pressure at a given point in time after the
initial point in time.
In some embodiments, determining the pressure difference relative
to the at least one previously measured pipette pressure includes
measuring the pipette pressure at an initial point in time and
determining the pressure difference relative to the least one
previously measured pipette pressure at a given point in time after
the initial point in time. Some embodiments include that the given
point in time after the initial point in time corresponds to a
volume of gas present in the distal portion of the pipette tip at
the initial point in time.
Some embodiments of the present disclosure are directed to computer
program products that include a computer readable storage medium
having computer readable program code embodied in the medium. The
computer code may include computer readable code to perform any of
the operations as described herein.
Some embodiments of the present disclosure are directed to a
computer system that includes at least one processor and at least
one memory coupled to the processor. The at least one memory may
include computer readable program code embodied therein that, when
executed by the at least one processor causes the at least one
processor to perform any of the operations as described herein.
It is noted that aspects of the disclosure described with respect
to one embodiment, may be incorporated in a different embodiment
although not specifically described relative thereto. That is, all
embodiments and/or features of any embodiment can be combined in
any way and/or combination. These and other objects and/or aspects
of the present inventive concept are explained in detail in the
specification set forth below.
BRIEF DESCRIPTION OF THE DRAWINGS
Aspects of the present disclosure are illustrated by way of example
and are not limited by the accompanying figures with like
references indicating like elements.
FIG. 1 is a perspective view from the front of an automated
streaking apparatus according to some embodiments of the present
inventive subject matter.
FIG. 2 is a perspective view from the rear of the apparatus of FIG.
1 according to some embodiments of the present inventive subject
matter.
FIG. 3 is a perspective view from above a part of the apparatus of
FIG. 1 according to some embodiments of the present inventive
subject matter.
FIG. 4 is a perspective view of a pipette pressure detector
according to some embodiments of the present inventive subject
matter.
FIG. 5 is a flowchart illustrating operations in methods according
to some embodiments of the present inventive subject matter.
FIG. 6 is a flowchart illustrating operations in methods according
to some embodiments of the present inventive subject matter.
FIG. 7 is a graph of pressure values versus time according to some
embodiments of the present inventive subject matter.
FIG. 8 is a flowchart illustrating operations in methods according
to some embodiments of the present inventive subject matter.
FIG. 9 is a flowchart illustrating operations in methods according
to some embodiments of the present inventive subject matter.
FIG. 10 is a flowchart illustrating operations in systems according
to some embodiments of the present inventive subject matter.
FIG. 11 is a block diagram illustrating systems according to some
embodiments of the present inventive subject matter.
DETAILED DESCRIPTION
As discussed herein, systems, articles of manufacture, methods,
and/or computer program products of the present inventive subject
matter may provide an effective and efficient way to detect a
surface using a pipette and/or to position a pipette. Some
embodiments of the present inventive subject matter may provide the
ability to monitor and/or verify that a liquid sample volume is
correctly dispensed onto a surface of a target, such as a surface
of solid growth culture medium (e.g., agar). Thus, some embodiments
of the present inventive subject matter may reduce the risk of a
false negative. For example, if a pipette tip is not positioned
close enough to a surface, such as a surface of solid growth
culture medium (e.g., agar), when the liquid sample in the pipette
tip is dispensed from the pipette tip, the liquid sample may not be
dispensed or wicked off onto the surface. Instead, the liquid
sample may be wicked up onto the side of the pipette tip. Some
embodiments of the present inventive subject matter may provide the
ability to position a pipette tip attached to a pipette close to a
surface without lowering the tip too far such that it scratches or
gouges the surface, such as a surface of solid growth culture
medium (e.g., agar). Some embodiments of the present inventive
subject matter may improve the accuracy of detecting a surface of a
target, such as a surface of solid growth culture medium (e.g.,
agar), compared to other methods of detecting the surface of the
target. Thus, some embodiments of the present inventive subject
matter may more accurately position a pipette tip attached to a
pipette above a surface and may thereby reduce the risk of a false
negative. "Liquid" as used herein refers to a sample having a
viscosity suitable for aspirating and dispensing using a pipette,
but which may include solid particles. In some embodiments, the
liquid sample is a biological sample.
In some embodiments, systems, articles of manufacture, methods,
and/or computer program products of the present inventive subject
matter may be used with and/or in an automated apparatus. The
automated apparatus may be an apparatus for positioning a pipette
and/or for pipetting a liquid onto a surface of a target, such a
surface of solid growth culture medium (e.g., agar). In some
embodiments, the automated apparatus may be an apparatus for
inoculating and streaking a solid growth culture medium in a plate,
such as, for example, the apparatus illustrated in FIGS. 1 and
2.
Reference is now made to FIGS. 1 and 2, which are a perspective
view from the front and rear, respectively, of an automated
streaking apparatus according to some embodiments of the present
inventive subject matter. The apparatus includes a plate supply
(indicated by the letter A) that includes a plurality of input
plate cassettes 10 (only cassettes 10a and 10f are shown) supported
on an upper frame (not shown) for the supply of raw plates to the
apparatus, together with a plate store (indicated by the letter B)
that includes a plurality of output plate cassettes 11 (only
cassettes 11a and 11f are shown) also supported on the upper frame
for the storage of processed plates from the apparatus. Also shown
in FIG. 1 is an inoculation and streaking station (indicated by the
letter C).
In some embodiments, the plate supply A and the plate store B are
supported by the upper frame so as to be in front of a main gantry
12, along which various of operative carriages of the apparatus may
move, as will be explained below. The various parts of the
inoculation and streaking station C may be supported by a lower
frame (not shown).
Operatively engaged for sliding movement along the main gantry 12
is a plate supply carriage 14a and a plate store carriage 14b,
which form a part of a plate transfer feed mechanism and a plate
transfer store mechanism, respectively. These carriages are both
configured for movement along the main gantry 12 (in the x
direction) to move a plate (16a or 16b) from the plate supply A to
the inoculation and streaking station C and then to the plate store
B. The carriages 14a, 14b are also configured to provide movement
of a plate 16a, 16b along vertical guiderails 18a, 18b thereon to
raise and/or lower such plate 16a, 16b in the z direction to or
from the respective cassettes 10a to 10f, and 11a to 11f and to or
from either or both of the dual plate orientation mechanisms 20a,
20b.
In this respect, it can be seen that each of the carriages 14a, 14b
includes a plate support tray 22a, 22b upon which the plates 16a,
16b rest in transit, the plate support trays 22a, 22b being
suitably mounted to their respective carriages for the movement
described above. In some embodiments, the plates 16a, 16b may be
supplied and stored in their respective cassettes 10a-10f, 11a-11f
in an inverted orientation, such that their bottoms are uppermost
and their lids are lowermost.
Also configured for movement along the main gantry 12 are an
inoculating device 30 and a streaking device 40. In some
embodiments, both may be mounted upon a suitable carriage for
movement along the main gantry in the x direction. The inoculation
device 30 may include a pipette robot system controlled so as to be
able to access supply 32 of pipette tips and a sample supply system
34 that includes a number of supply tubes 36, and to access a plate
work position (one such position shown in FIG. 2 by the letter D)
for inoculation purposes. The streaking device 40 may include a
streaking robot system controlled so as to be able to access a
streaking applicator supply 42 that, in some embodiments, includes
four applicator supply cartridges 46 received in four corresponding
cartridge holders 44.
In some embodiments, the inoculation and streaking station C of the
apparatus includes dual plate work positions D and dual rotation
devices 52a, 52b for the streaking of dual plates 16c, 16d as shown
in FIG. 2 in the dual plate work positions D, and dual plate
orientation mechanisms 20a, 20b, the location of which is indicated
in FIGS. 1 and 2 by the reference numerals 50a and 50b. While FIG.
2 generally shows de-lidded plates 16c, 16d in the plate work
positions D underneath dual sensors 54a, 54b, FIG. 1 shows dual
plates 16e, 16f being orientated and de-lidded by the dual
orientation mechanisms 20a, 20b. It will of course be appreciated
that such a dual configuration is not essential for an apparatus in
accordance with the present invention, and that single such
stations and devices could be used. Indeed, an apparatus that
includes three or four or more such stations and devices is also
envisaged.
In some embodiments, the inoculating and streaking station C is the
general location within the apparatus where the main functions of
the apparatus occur, which location is generally centered around
the plate work positions D. In some embodiments, the plate work
positions D are defined by the physical location in the apparatus
of the sensors 54a, 54b, which may be rigidly mounted to respective
sensor mounting frames 58a, 58b. The apparatus may also include
dual plate platforms for supporting a plate, although the
combination of FIGS. 1 and 2 shows four such platforms, being the
dual platforms 60a, 60b in the positions shown in FIG. 1, and the
platforms 62a, 62b shown in FIG. 2. In this respect, these figures
each show two platforms (in different positions) simply for the
sake of description.
In some embodiments, each cassette 10a, 11a may be able to hold
multiple plates within their inner chambers. For example, cassette
10a may hold multiple plates for the purpose of providing raw
plates to the apparatus for subsequent processing, and cassette 11a
may hold multiple plates for the purpose of storing processed
plates following inoculation and streaking in the apparatus. As can
be seen in FIGS. 1 and 2, each of the cassettes 10a, 11 a also
interacts with its respective carriage 14a, 14b to capture a plate,
from below, on the respective trays 22a, 22b due to respective
internal engaging and plate release/lock means (not shown).
In some embodiments, the inoculating device 30 of the apparatus of
the present invention may be any device that is able to obtain and
hold a sample, generally in a liquid form, and transfer that sample
to a surface, such as the surface of a medium in a positioned
plate. In some embodiments, the inoculating device 30 may be a
pipette 31 mounted to a robot system (not shown) so as to be
movable in the z-direction, as well as the x- and y-directions
along the main gantry 12 as mentioned above. In some embodiments,
the pipette 31 may include a pressure transducer configured to
monitor pressure and/or vacuum profiles in an internal portion of
the pipette 31.
Reference is now made to FIG. 3, which is a perspective view from
above a part of the apparatus of FIG. 1 according to some
embodiments of the present inventive subject matter. The pipette 31
may include a pipette tip 33 releasably secured thereto. In some
embodiments, the pipette tip 33 may include a filter and/or may be
disposable. The pipette tip 33 may be releasably secured and/or
attached to the pipette 31 in a manner that permits easy disposal
of the pipette tip 33, such as disposal after inoculation has been
affected. In some embodiments, the pipette 31 may be programmable
for aspirating and/or dispensing various sample volumes at given
points in time. In some embodiments, the pipette 31 may include a
positional height referencing system, such as, but not limited to,
a positional height z-direction referencing system. The positional
height referencing system may be configured to determine in three
dimensional space the height location of the pipette tip 33
relative to the datum level and reference points of a platform,
such as platform 60a, 60b, 62a, 62b, as will be described below,
and/or relative to a notional action line.
In some embodiments, the pipette robot system may be configured to
move the pipette 31 to access a pipette tip supply 32, which may
include a rack of pipette tips 33, to access the biological sample
station 34, which may include a rack of sample containers such as
sample tubes, to access the plate work position D in the
inoculating and streaking station C, and/or to access a tip waste
disposal area or chute. The pipette robot system, pipette 31,
and/or pipette tip 33 may include suitable tip securing means that
is configured for the pipette tip 33 to be secured to the pipette
31. In some embodiments, the pipette robot system, pipette 31,
and/or pipette tip 33 may be configured to obtain and hold a
sample, to dispense sample, and to dispose of a used pipette tip
33.
Referring again to FIG. 3, FIG. 3 illustrates some of the
structures used for operations that may occur in the plate work
position D and illustrates a plate platform 60a with a plate bottom
19 in a centralized and clamped position in the plate work position
D. In some embodiments, the plate platform 60a may include a plate
clamping member 75 in the form of three movable lugs operated by a
camming device (not shown), which lugs may be configured to
function as a plate centralizing means for centralizing the
position of the plate bottom 19 on the platform 60a.
In some embodiments, the plate work position D may include a
notional action line fixed in two dimensions (x,y) in a given
position, together with a datum level Y (e.g., the surface upon the
plate platform 60a). The action line is herein referred to as being
a "notional" action line given that it will not be a visible action
line and also will not have a determined position in three
dimensional space until the height of the surface 70 of the medium
in the plate bottom 19 is determined.
In some embodiments, the plate work position D may include a
position detector, such as, for example, 1, 2, 3, 4, or more
position detectors. The position detector may be configured and/or
used to locate the surface 70 in a plate bottom 19 and/or to detect
the z-position of medium in the plate bottom 19. In some
embodiments, the position detector may include a sensor 54a. In
some embodiments, the plate work position D may include a datum
level Y, which may be the uppermost surface upon the plate platform
60a. In some embodiments, the sensor 54a may include an ultrasonic
sensing device 55a having an ultrasonic beam focusing element that
is configured to provide a focused beam on the surface 70 and/or
within a sensing region that is central to the notional action
line. The sensor 54a may be rigidly mounted via a sensor support
arm 58a, thereby defining the general location of the plate work
position D. In some embodiments, the sensor 54a may be mounted so
that it is above the plate work position D and is operatively
adjacent the plate bottom 19 held immediately therebelow in the
plate platform 60a, the plate bottom 19 having its surface 70 open
upwardly. In some embodiments, the sensor 54a may be positioned
over a plate bottom 19, but may not be positioned over the starting
position for dispensing a sample from a pipette tip 33.
In some embodiments, the sensor 54a may be configured to sense the
surface 70 and/or measure the distance to the surface 70. The
measured distance may then be referenced to the datum level Y to
determine a surface positional reference relative to the datum
level Y in one dimension (z) for the surface 70 in the plate bottom
19. In this manner, it will be appreciated that the surface 70 can
thus be located in at least the z dimension by virtue of the
determination of this surface positional reference. This may
effectively determine the height of the medium in the plate bottom
19, at least with reference to that datum level Y. In this respect,
and as can be seen in the figures, the datum level Y is a surface
that forms a part of the plate platform 60a upon which the plate is
clamped and supported. Therefore, in some embodiments, the
determination of the surface positional reference effectively
determines the height of the medium with reference to the plate
platform 60a upon which it rests.
In some embodiments, the surface positional reference may be used
together with the notional action line to determine the line G in
three dimensions (x,y,z) that is representative of a line across
the surface 70 in the positioned plate.
In some embodiments, the notional three dimensional action line
that is represented by the line G across the surface 70 of the
medium in the plate bottom 19 will be specific to the medium in
that plate bottom 19 only, and may be a different three dimensional
action line compared to the surface of the next plate processed in
the plate work position D. In some embodiments, the given (x, y)
position of the notional action line is, with reference to the
circular plate bottom 19, located such that the notional action
line will be a radial line for a circular plate. In some
embodiments, this means that the line G, which represents the
action line in three dimensions (x, y, z), will also be a radial
line.
In some embodiments, once the position of the three dimensional
action line G for a medium in a given positioned plate in three
dimensional space has been determined, the sample may be deposited
onto the surface 70 of the medium along the line G. As used herein,
the reference to a sample being dispensed "along" a line or there
being inoculation "along" a line, is intended to include a variety
of forms of dispensing/inoculation. For example, a sample may be
dispensed continuously along the full length of the line, or may be
dispensed semi-continuously along the line, such as may be provided
by a series of discrete deposits in the form of dots and/or dashes.
Similarly, some embodiments include that a sample may be dispensed
in a substantially non-linear form.
In some embodiments, the position detector may include a camera.
The camera may be configured and/or used to detect the z-position
of a pipette tip 33. In some embodiments, the camera and/or sensor
54a may be used to determine the three dimensional action line G
for a medium.
In some embodiments, a pipette pressure detector may be used to
determine the surface of medium in a positioned plate. Some
embodiments include using a pipette pressure detector to determine
the surface of medium in a positioned plate after and/or during a
camera and/or sensor 54a determining the three dimensional action
line G for the medium. In some embodiments, the pipette pressure
detector may more accurately determine the surface of the medium
than the camera and/or sensor 54a.
In some embodiments, a pipette pressure detector may be used to
determine and/or verify dispensing of a fluid from the pipette tip
33 attached to the pipette 31. Some embodiments include detecting
that a liquid is/was present in pipette tip 33 after a given amount
of the liquid has been dispensed from the pipette tip 33 using a
pipette pressure detector. Some embodiments include determining
that a sufficient amount of liquid is/was present in the pipette
tip 33 after a given amount of the liquid was dispensed from the
pipette tip 33 using a pipette pressure detector. Some embodiments
include determining and/or verifying dispensing of a fluid from the
pipette tip 33 attached to the pipette 31 after the pipette
pressure detector has determined and/or detected the surface of
medium in a positioned plate. In some embodiments, the fluid is a
liquid.
In some embodiments, a pipette pressure detector may be used to
detect and/or determine the integrity of the pipette tip 33
attached to the pipette 31. Some embodiments include using the
pipette pressure detector to detect and/or determine that the
pipette tip 33 is functioning properly and/or is suitable for use.
In some embodiments, determining that the pipette tip 33 is
suitable for use includes determining that the pipette tip 33
attached to pipette 31 is suitable to aspirate and dispense a
liquid. Some embodiments include using the pipette pressure
detector to detect and/or determine that the pipette tip 33 is not
functioning properly and/or is not suitable for use. In some
embodiments, the pipette pressure detector may be used to detect
and/or determine the integrity of the pipette tip 33 prior to
aspirating a liquid sample into the pipette tip 33 and/or prior to
determining the surface of medium in a positioned plate.
In some embodiments, a pipette pressure detector may be used to
detect a droplet at the distal end of pipette tip 33 attached to
the pipette 31 and/or the formation of a droplet at the distal end
of pipette tip 33 attached to the pipette 31. Some embodiments
include using the pipette pressure detector to detect a droplet
and/or the formation of a droplet at the distal end of pipette tip
33 after the pipette pressure detector has determined the surface
of medium in a positioned plate and/or after the pipette 31 has
been positioned at a location for dispensing a liquid sample.
In some embodiments, a pipette pressure detector may be used to
detect a clog in the pipette tip. In some embodiments, a pipette
pressure detector may be used to detect an empty pipette tip (i.e.,
a pipette tip with no liquid present in the pipette tip).
The pipette pressure detector may include a pressure transducer and
a pressure data module. In some embodiments, the pressure
transducer and pressure data module may be integrated into a single
package. In some embodiments, the pipette pressure detector may be
mounted onto the pipette 31 and/or may be integral to the pipette
31. The pressure transducer may be in fluidic communication with an
internal portion of the pipette 31 and/or may be built-in to the
pipette 31. The pressure data module may receive and/or transmit
signals corresponding to a pressure at an internal portion of the
pipette 31. Some embodiments include the pressure data module
receiving signals from the pressure transducer. In some
embodiments, the pressure data module may convert a signal received
from the pressure transducer to a different signal and/or signal
format, such as, for example, from an analog signal to a digital
signal. In some embodiments, the pipette pressure detector may be
used to calculate the z-position relative to the surface 70 to move
the pipette tip 33 to a desired position before the sample is
dispensed from the pipette tip 33.
Some embodiments include using a pipette pressure detector to
detect that the surface of a medium in a given plate is at a
desired position for dispensing a sample from the pipette tip 33.
In some embodiments, the desired position may be over the starting
position for dispensing the sample from the pipette tip 33. Some
embodiments include dispensing a liquid sample from the pipette tip
33 after a pipette pressure detector has determined the position of
the surface of a medium in a given plate relative to the pipette
tip 33 and/or after the pipette 31 has been moved to a z-position
above the surface.
In some embodiments, while the liquid sample is being dispensed
from the pipette tip 33, a pipette pressure detector may detect a
droplet and/or the formation of a droplet at the distal end of
pipette tip 33 attached to pipette 31. Some embodiments include
stopping dispensing of the liquid sample from pipette tip 33 upon
detecting the droplet and/or the formation of the droplet at the
distal end of pipette tip 33 attached to pipette 31. In some
embodiments, after detecting the droplet and/or the formation of
the droplet at the distal end of pipette tip 33, the pipette 31 may
be moved to a different position, such as, for example, a different
position above the surface, and/or a second droplet may be detected
at the distal end of pipette tip 33 attached to pipette 31.
In some embodiments, upon dispensing a liquid sample from the
pipette tip 33 onto the surface 70 of the medium, a pipette
pressure detector may be used to determine and/or verify that a
remaining volume and/or a sufficient amount of the liquid sample
is/was present in the pipette tip 33. In some embodiments, upon
dispensing a liquid sample from the pipette tip 33 onto the surface
70 of the medium, the dispensed liquid may be streaked using the
streaking device 40. In some embodiments, a line of spaced apart
contact surfaces of a streaking applicator may contact at least a
portion of the dispensed liquid, optionally along line G, on the
surface 70 of the medium in the plate bottom 19. In some
embodiments, the streaking applicator may contact the dispensed
liquid and/or medium with a given contact pressure. In some
embodiments, the given contact pressure may be suitable for the
particular streaking applicator being used, for the composition of
the liquid sample, and/or for the particular solid growth medium
being used. In some embodiments, the given contact pressure may be
such that the liquid is spread when the platform 60a is rotated and
such that the streaking applicator does not undesirably gouge the
surface of the medium.
As those of skill in the art will understand and appreciate, the
above apparatus described in reference to FIGS. 1-3 is described
only to provide an example embodiment in which systems, articles of
manufacture, methods, and/or computer program products of the
present inventive subject matter may be embodied. The above
discussion is not intended to limit the systems, articles of
manufacture, methods, and/or computer program products of the
present inventive subject matter to the above-referenced apparatus.
Instead, the apparatus described above in reference to FIGS. 1-3 is
a non-limiting example and the systems, articles of manufacture,
methods, and/or computer program products of the present inventive
subject matter may be applied to any system, article of
manufacture, method, and/or computer program product in which
pipette controls may be utilized, in which detecting a surface
relative to a pipette may be desired, and/or in which determining a
pipette position relative to a surface may be desired.
Reference is now made to FIG. 4, which is a perspective view of a
pipette 80 according to some embodiments of the present inventive
subject matter. In some embodiments, the pipette 80 may include a
pipette tip 88 releasably attached to the pipette 80. In some
embodiments, systems, articles of manufacture, methods, and/or
computer program products of the present inventive subject matter
may include a pipette pressure detector 82. The pipette pressure
detector 82 may include a pressure transducer 84 and a pressure
data module 86. In some embodiments, the pressure transducer 84 and
pressure data module 86 may be integrated into a single package. In
some embodiments, the pipette pressure detector 82 may be mounted
onto the pipette 80 and/or may be integral to the pipette 80.
The pressure transducer 84 may be in fluidic communication with the
pipette 80 and/or may be built-in to the pipette 80. The pressure
data module 86 may receive and/or transmit signals corresponding to
a pressure at an internal portion of the pipette 80. Some
embodiments include the pressure data module 86 receiving signals
from the pressure transducer 84. In some embodiments, the pressure
data module 86 may convert a signal received from the pressure
transducer 84 to a different signal and/or signal format, such as,
for example, from an analog signal to a digital signal.
The pipette pressure detector 82 may measure pressure and/or vacuum
profiles at an internal portion of a pipette. Example pipette
pressure detectors that include a pipette include, but are not
limited to, those commercially available from Tecan under the name
CAVRO.RTM. and from Hamilton Company under the name ZEUS.TM.. In
some embodiments, the pipette pressure detector 82 may use
real-time pressure data to detect a surface 90 and/or to determine
a position of the pipette 80 and/or pipette tip 88 above a surface
90.
In some embodiments, the pipette pressure detector 82 may use
pressure data to determine and/or verify dispensing of a fluid in
the pipette tip 88 attached to the pipette 80. In some embodiments,
the fluid is a liquid. Some embodiments include determining and/or
verifying dispensing of a fluid from the pipette tip 88 attached to
the pipette 80 after a given volume of fluid has been dispensed. In
some embodiments, the pipette pressure detector may be used to
determine and/or verify that a sufficient volume of liquid is/was
present in the pipette tip 88 after a portion of the liquid was
dispensed.
In some embodiments, the pipette pressure detector 82 may use
pressure data to detect and/or determine the integrity of the
pipette tip 88. In some embodiments, the pipette pressure detector
82 may use pressure data to determine that the pipette tip 88 is
properly functioning and/or is suitable for use. In some
embodiments, determining that the pipette tip 88 is suitable for
use includes determining that that the pipette tip 88 attached to
pipette 80 is suitable to aspirate and dispense a liquid. Some
embodiments include using the pipette pressure detector to detect
and/or determine that the pipette tip 88 is not functioning
properly and/or is not suitable for use. Some embodiments include
aspirating a gas into the pipette tip 88 while the pipette pressure
detector 82 may be measuring pressure and/or vacuum profiles at an
internal portion of the pipette 80 to determine whether the pipette
tip 88 attached to pipette 80 is properly functioning and/or
suitable for use.
In some embodiments, the pipette pressure detector 82 may use
real-time pressure data to detect a droplet at the distal end of
pipette tip 88 attached to pipette 80 and/or the formation of a
droplet at the distal end of pipette tip 88 attached to a pipette
80. In some embodiments, the pipette pressure detector 82 may be
used to detect a clog in the pipette tip 88. In some embodiments,
the pipette pressure detector 82 may be used to detect an empty
pipette tip (i.e., a pipette tip with no liquid present in the
pipette tip).
The pipette pressure detector 82 may perform and/or be utilized in
one or more operations of the methods and systems described
below.
Reference is now made to FIG. 5, which is a flowchart illustrating
operations of methods according to some embodiments of the present
inventive subject matter. The methods may include positioning a
pipette at a first distance above a surface using a first position
detector at block 100 and positioning the pipette at a second
distance above the surface using a second position detector at
block 120, with the second position detector being different than
the first position detector and the second distance being less than
the first distance. Some embodiments include that the first
position detector uses a first technology for determining a
position, such as, for example an optical and/or ultrasonic
position detector, among others. Some embodiments provide that the
second position detector uses a second technology that is different
than the first technology. The first and/or second distance may
include a defined position above the surface and/or a position
range above the surface.
In some embodiments, the second position detector may include a
pipette pressure detector and the first position detector may use a
metric other than pressure. The pipette pressure detector may
include a pressure transducer and may measure pressure at an
internal portion of a pipette. The pipette pressure detector may be
as described above in reference to FIG. 4 and duplicate discussion
thereof may be omitted herein for the purpose of discussing FIG. 5.
In some embodiments, the pipette pressure detector may use
real-time pressure data to detect the surface and/or determine the
second distance. In some embodiments, the first position detector
may include an optical position detector, such as, but not limited
to, a camera, and/or an ultrasonic position detector, which may
include a sensor. In some embodiments, the first position detector
may be used to determine the distance to the surface and/or the
surface of medium (e.g., agar) present a container, such as a
plate.
Some embodiments include, prior to positioning the pipette at the
second distance, contacting the surface with a tip of the pipette
at block 110. In some embodiments, the tip of the pipette is the
distal end of a pipette tip that is attached to the pipette (i.e.,
the end of the pipette tip farthest from the pipette).
Some embodiments include positioning the pipette at the first
distance at block 100 at any suitable distance above the surface.
In some embodiments, the first distance above the surface is a
known distance, which may be determined using the first position
detector. In some embodiments, the first distance may be greater
than the degree of error in determining the surface with the first
position detector. For example, if the first position detector has
a degree of error off 0.5 mm in detecting the surface, then the
first position may be at least greater than 0.5 mm above the
surface, such as for example, in a range of 0.6 mm to 1 mm above
the surface. In some embodiments, the first distance may be in a
range of about 0.3 mm to about 40 cm above the surface, such as,
for example, in a range of about 0.3 mm to about 1 mm, about 0.5 mm
to about 1 mm, about 0.5 mm to about 5 cm, about 1 mm to about 10
cm, about 1 mm to about 1 cm, about 2 cm to about 10 cm, or about
10 cm to about 40 cm. In some embodiments, the first distance may
be about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8,
or 9 mm above the surface or about 1, 2, 3, 4, 5 cm or more above
the surface. The first distance values provided herein are examples
and are not intended to limit the scope of the invention. For
example, the first distance may be less than 0.3 mm or greater than
40 cm.
The second distance may be any suitable distance above the surface
that is less than the first distance. In some embodiments, the
second distance may be in a range of about 0.05 mm to about 1 cm
above the surface, such as, for example, in a range of about 0.05
mm to about 5 mm, about 0.1 mm to about 1 mm, about 0.1 mm to about
0.5 mm, or about 1 mm to about 1 cm. In some embodiments, the
second distance may be about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6,
0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm above the
surface. The second distance values provided herein are examples
and are not intended to limit the scope of the invention. For
example, the second distance may be less than 0.05 mm or greater
than 1 cm.
Some embodiments include positioning the distal end of a pipette
tip attached to the pipette at the first distance and/or second
distance. In some embodiments, the first and/or second distance may
vary depending on the liquid sample type and/or the surface type
(e.g., the type of the growth culture medium). In some embodiments,
the surface may not be level and/or may not include uniform surface
characteristics.
In some embodiments, the second position detector may improve the
accuracy of determining the location of and/or distance to the
surface and/or detecting the surface. Some embodiments include the
second position detector positioning the pipette and/or detecting
the surface with an accuracy in a range of .+-. about 0.03 mm to
about 0.1 mm, such as, for example, about 0.03 mm to about 0.05 mm
or about 0.04 mm to about 0.06 mm. In some embodiments, the second
position detector positions the pipette and/or detects the surface
with an accuracy of about 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09,
or 0.1 mm. The accuracy values provided herein for the second
position detector are examples and are not intended to limit the
scope of the invention. For example, the accuracy for the second
position detector may be less than 0.03 mm or greater than 0.1 mm.
In some embodiments, the second position detector determines and/or
detects the surface at a position where or close to where the
pipette may initially dispense a liquid from an attached pipette
tip, such as, for example, at a position in the x- and/or
y-direction where the pipette will dispense the liquid.
Reference is now made to FIG. 6, which is a flowchart illustrating
operations of methods according to some embodiments of the present
inventive subject matter. In some embodiments, the methods may
include measuring a pipette pressure at an internal portion of a
pipette at block 200. In some embodiments, measuring a pipette
pressure at an internal portion of a pipette at block 200 may
include generating a plurality of pipette pressure values. In some
embodiments, measuring the pipette pressure at an internal portion
of the pipette at block 200 is carried out using a pipette pressure
detector including a pipette as described above in reference to
FIG. 4, the duplicate discussion of the pipette pressure detector
and pipette is omitted herein for the purposes of discussing FIG.
6. Some embodiments include measuring the pipette pressure at block
200 with a liquid and/or a gas in a pipette tip attached to the
pipette.
Measuring the pipette pressure at block 200 may include measuring
the pipette pressure at given time intervals. Any suitable time
interval may be used to measure the pipette pressure. In some
embodiments, the time interval may depend on whether the pipette
and/or surface is/are moving and, if so, the rate of movement
and/or the time interval may depend on whether gas is being
aspirated into the pipette and, if so, the rate of aspiration. Some
embodiments include measuring the pipette pressure at block 200
every 0.1 to 100 milliseconds, such as, for example, every 1 to 50,
0.1 to 10, 1 to 10, 10 to 50, or 50 to 100 milliseconds. In some
embodiments, pipette pressure at block 200 is measured every 0.5,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, or more milliseconds.
The given time intervals provided herein are examples and are not
intended to limit the scope of the invention. For example, the
pipette pressure may be measured at time intervals less than 0.1
milliseconds or greater than 100 milliseconds.
In some embodiments, measuring the pipette pressure at block 200
includes measuring the pipette pressure while aspirating gas into a
pipette tip attached to the pipette and/or while the pipette is
moving toward a surface and/or the surface is moving toward the
pipette. Some embodiments include aspirating a gas into a pipette
tip attached the pipette. The gas may be aspirated at any suitable
flow rate. In some embodiments, the flow rate may depend on the
sample type including the sample viscosity and/or if the pipette
tip includes a filter. In some embodiments, the gas may be
aspirated into the pipette tip at a constant flow rate. Some
embodiments include aspirating a gas at a flow rate in a range of
about 1 .mu.L/s to about 100 mL/s, such as, for example, in a range
of about 1 .mu.L/s to about 100 .mu.L/s, about 5 .mu.L/s to about
40 .mu.L/s, or about 1 mL/s to about 100 mL/s. In some embodiments,
a gas may be aspirated at a flow rate of about 5, 10, 15, 20, 25,
30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100 .mu.L/s or
more. The flow rates provided herein for aspirating a gas are
examples and are not intended to limit the scope of the invention.
For example, the flow rate for aspirating a gas may be less than 1
.mu.L/s or greater than 100 mL/s. Some embodiments include
measuring the pipette pressure at block 200 while aspirating gas
into a pipette tip attached to the pipette and while the pipette is
moving toward a surface.
In some embodiments, measuring the pipette pressure at block 200
includes measuring the pipette pressure while the pipette is moving
toward a surface. The pipette may move toward the surface in any
direction. In some embodiments, the pipette may move downward in a
z-direction toward the surface. Some embodiments include the
pipette moving toward the surface at any suitable rate. In some
embodiments, the pipette may move toward the surface, such as, for
example, downward in the z-direction, at a rate in a range of about
0.1 mm/s to about 10 mm/s, such as, for example, in a range of
about 0.5 mm/s to about 7 mm/s, about 1 mm/s to about 10 mm/s, or
about 1 mm/s to about 5 mm/s. In some embodiments, the pipette may
move toward the surface, such as, for example, downward in the
z-direction, at a rate of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm/s or more. The rates of
movement for a pipette provided herein are examples and are not
intended to limit the scope of the invention. For example, the rate
of movement may be less than 0.1 mm/s or greater than 10 mm/s.
In some embodiments, measuring the pipette pressure at block 200
includes measuring the pipette pressure while the surface is moving
toward the pipette. The surface may move toward the pipette in any
direction. In some embodiments, the surface may move upward in a
z-direction toward the pipette. Some embodiments include the
surface moving toward the pipette at any suitable rate. In some
embodiments, the surface may move toward the pipette, such as, for
example, upward in the z-direction, at a rate in a range of about
0.1 mm/s to about 10 mm/s, such as, for example, in a range of
about 0.5 mm/s to about 7 mm/s, about 1 mm/s to about 10 mm/s, or
about 1 mm/s to about 5 mm/s. In some embodiments, the surface may
move toward the pipette, such as, for example, upward in the
z-direction, at a rate of about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm/s or more. The rates of
movement for a surface provided herein are examples and are not
intended to limit the scope of the invention. For example, the rate
of movement may be less than 0.1 mm/s or greater than 10 mm/s.
Referring again to FIG. 6, some embodiments include determining a
pressure difference relative to a previously measured pipette
pressure value at block 210. In some embodiments, any previously
measured pipette pressure value may be used to determine the
pressure difference at block 210. In some embodiments, the pressure
difference may be determined using the most recently pipette
pressure value and the pipette pressure value measured immediately
preceding the most recently measured pipette pressure value. Some
embodiments include subtracting the previously measured pipette
pressure value from the most recently measured pipette pressure
value to obtain the pressure difference at block 210.
Some embodiments include estimating a rate of change in pipette
pressure at block 220. In some embodiments, estimating the rate of
change in pipette pressure at block 220 includes mathematically
weighting the pressure difference determined at block 210 to
provide a weighted pressure difference. Weighting may include
multiplying an original value by a given weighting factor to
provide a weighted value. In some embodiments, estimating the rate
of change in pipette pressure at block 220 includes summing the
weighted pressure difference with a weighted previously calculated
rate of change in pipette pressure. In some embodiments, the
weighted previously calculated rate of change in pipette pressure
may be estimated using the pipette pressure value immediately
preceding the most recently measured pipette pressure value. Some
embodiments include weighting the pressure difference by about 0%
to 49% and weighting the previously calculated rate of change in
pipette pressure by about 51% to about 100%. In some embodiments,
the pressure difference may be weighted by about 5% to 25% and the
previously calculated rate of change in pipette pressure may be
weighted by about 75% to about 95%. In some embodiments, weighting
the pressure difference and/or the previously calculated rate of
change in pipette pressure may function as a single-pole filter or
the rate of change data.
In some embodiments, estimating the rate of change in pipette
pressure at block 220 includes estimating the rate of change in
pipette pressure using the following equation: Rate of change in
pipette pressure=(XP.sub.n)+(YP.sub.n-1), in which X is a first
weighting factor, Y is a second weighting factor, P.sub.n is a most
recently estimated pressure difference value, and P.sub.n-1 is the
pressure difference value immediately preceding P.sub.n, the most
recently estimated pressure difference value. In some embodiments,
the first weighting factor and the second weighting factor may be
the same or different.
Some embodiments include estimating a statistical variable at block
230. In some embodiments, the statistical variable corresponds to
the rate of change in pipette pressure estimated at block 220. In
some embodiments, estimating the statistical variable at block 230
includes estimating an average rate of change in pipette pressure.
In some embodiments, estimating the statistical variable at block
230 includes estimating a ratio relating to the rate of change in
pipette pressure. The ratio relating to the rate of change in
pipette pressure may include the rate of change in pipette pressure
and the average rate of change in pipette pressure.
For example, in some embodiments, estimating the statistical
variable at block 230 may be expressed using the following
equation:
Average rate of change in pipette pressure=(P.sub.1+P.sub.2+ . . .
P.sub.n)/n, in which P.sub.1, P.sub.2, and P.sub.n are each
pressure difference values with P.sub.n being the most recently
estimated pressure difference value, and n is the total number of
pipette pressure values measured. Thus, in some embodiments, the
average rate of change in pipette pressure is obtained by taking
the sum of all the pressure difference values estimated divided by
the total number of pipette pressure values measured. In some
embodiments, P.sub.1, P.sub.2, and P.sub.n may each independently
be weighted pressure difference values. In some embodiments, the
average rate of change in pipette pressure is obtained by taking
the sum of all the pipette pressure values measured divided by the
total number of pipette pressure values measured. In some
embodiments, the average rate of change in pipette pressure may
correspond to an average taken over the entire sampling period,
whereas some embodiments may provide that the average is a moving
average taken over only a portion of the sampling period.
In some embodiments, estimating the statistical variable at block
230 may be expressed using the following equation: Ratio relating
to the rate of change in pipette pressure=absolute
value(P.sub.n/P.sub.average), in which P.sub.n is the most recently
estimated pressure difference value and P.sub.average is the
average pipette pressure. In some embodiments, P.sub.n may be a
weighted pipette difference value. In some embodiments, the average
pipette pressure may be determined as described above in regard to
the average rate of change in pipette pressure.
Some embodiments include comparing the statistical variable to a
pipette pressure related threshold at block 240. Some embodiments
include two or more pipette pressure related thresholds, such as,
for example, 2, 3, 4, 5 or more pipette pressure related
thresholds. Some embodiments include a pipette pressure related
threshold that may depend on and/or be tuned based on the pipette,
the volume of fluid (i.e., liquid and/or gas) present in a pipette
tip, the rate of aspiration or dispense, and/or the fluid type
and/or properties thereof. In some embodiments, a pipette pressure
related threshold may be empirically determined.
In some embodiments, the pipette pressure related threshold may be
determined using any suitable rate of aspiration and/or rate of
movement. In some embodiments, the pipette pressure related
threshold may be determined with a rate of aspiration in a range of
about 1 .mu.L/s to about 100 mL/s, such as, for example, in a range
of about 1 .mu.L/s to about 100 .mu.L/s, about 5 .mu.L/s to about
40 .mu.L/s, or about 1 mL/s to about 100 mL/s. In some embodiments,
the pipette pressure related threshold may be determined with a
rate of aspiration of about 5, 10, 15, 20, 25, 30, 35, 40, 45, 50,
55, 60, 65, 70, 75, 80, 85, 90, 100 .mu.l/s or more. The rates of
aspiration for determining a pipette pressure related threshold
provided herein are examples and are not intended to limit the
scope of the invention. For example, the rate of aspiration for
determining a pipette pressure related threshold may be less than 1
.mu.L/s or greater than 100 mL/s. The rate of aspiration may be the
rate at which a gas is aspirated into a pipette tip attached to a
pipette. In some embodiments, the pipette pressure related
threshold is determined with a rate of aspiration that is the same
as the rate at which a pipette aspirates gas into a pipette tip
while the pipette pressure is being measured at block 200.
In some embodiments, the pipette pressure related threshold may be
determined with a rate of movement in a range of about 0.1 mm/s to
about 10 mm/s, such as, for example, in a range of about 0.5 mm/s
to about 7 mm/s, about 1 mm/s to about 10 mm/s, or about 1 mm/s to
about 5 mm/s. In some embodiments, the pipette pressure related
threshold may be determined with a rate of movement of about 0.1,
0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9,
10 mm/s or more. The rates of movement for determining a pipette
pressure related threshold provided herein are examples and are not
intended to limit the scope of the invention. For example, the rate
of movement for determining a pipette pressure related threshold
may be less than 0.1 mm/s or greater than 10 mm/s. In some
embodiments, the pipette pressure related threshold is determined
with a rate of movement that is the same as the rate at which a
pipette moves toward a surface, such as downward in the z-direction
toward a surface, while the pipette pressure is being measured at
block 200. Some embodiments include determining the pipette
pressure related threshold when the pipette is moving downward in
the z-direction toward the surface.
Referring again to FIG. 6, comparing the statistical variable to
the pipette pressure related threshold at block 240 may include
using two or more pipette pressure related thresholds. In some
embodiments, a first value may be compared to a first pressure
related threshold and the statistical variable may be compared to a
second pressure related threshold. In some embodiments, the first
value may be a rate of change in pipette pressure and the
statistical variable may be a ratio of the rate of change in
pipette pressure divided by an average rate of change in pipette
pressure. In some embodiments, the statistical variable may the
absolute value of the ratio of the rate of change in pipette
pressure divided by an average rate of change in pipette pressure.
In some embodiments, the rate of change in pipette pressure may be
estimated at block 220 and the ratio may be estimated at block 230.
In some embodiments, the first pressure related threshold may be a
rate of change in pipette pressure threshold and the second
pressure related threshold may be a pipette pressure ratio
threshold. Some embodiments include determining and/or detecting
contact with a surface at block 260 when the rate of change in
pipette pressure is less than or equal to the rate of change in
pipette pressure threshold and the ratio of the rate change in
pipette pressure divided by the average rate of change in pipette
pressure is greater than or equal to the pipette pressure ratio
threshold.
Some embodiments include estimating a pipette position at block
250. Estimating the pipette position at block 250 may include
estimating the position of a pipette tip relative to a surface. In
some embodiments, estimating the pipette position at block 250
includes determining and/or detecting contact with a surface at
block 260. Some embodiments include determining that a surface is
not in contact with the pipette at block 260 and, responsive to
determining that the surface is not in contact with the pipette,
continuing to estimate the pipette position. Continuing to estimate
the pipette position may include repeating one or more operations
described in FIG. 6.
In some embodiments, estimating the pipette position at block 250
includes determining that a surface is in contact with the pipette
at block 260. In some embodiments, determining that the surface is
in contact with the pipette at block 260 includes determining that
the distal orifice of a pipette tip attached to the pipette begins
to seal and/or has sealed with the surface. In some embodiments,
determining that the surface is in contact with the pipette at
block 260 includes detecting at least two consecutive data points
(e.g., 2, 3, 4, 5, or more consecutive data points) that indicate
contact to the surface with the pipette. The at least two
consecutive data points may indicate the point at which the distal
orifice of a pipette tip attached to the pipette begins to seal
and/or has sealed with the surface.
In some embodiments, determining that the surface is in contact
with the pipette at block 260 includes detecting an inflection
point in the pipette pressure data obtained by measuring the
pipette pressure over a given period of time. The inflection point
may be the point at which a pipette tip attached to the pipette
contacts the surface and/or the point at which the distal orifice
of a pipette tip attached to the pipette begins to seal and/or has
sealed with the surface. Referring briefly to FIG. 7, which is a
graph of pressure values versus time according to some embodiments
of the present inventive subject matter, in some embodiments, the
inflection point may be a point preceding a drop or decrease in
pressure value. Some embodiments may include a significant drop or
decrease in pressure value after the inflection point. In some
embodiments, the pressure values prior to the inflection point may
increase in value.
Referring again to FIG. 6, some embodiments include, responsive to
determining that the surface is in contact with the pipette,
stopping the movement of the pipette and/or surface and/or
adjusting the position of the pipette and/or surface so that the
pipette is at a defined position above the surface. In some
embodiments, movement of the pipette toward the surface is stopped
and the pipette is moved to a defined position above the surface.
In some embodiments, movement of the surface toward the pipette is
stopped and the surface is moved to a defined position below the
pipette.
Some embodiments include, responsive to determining that the
surface is in contact with the pipette, stopping the aspiration of
gas.
Some embodiments include detecting a positioning error at block
270. In some embodiments, detecting a positioning error at block
270 may be responsive to determining that the pipette is not in
contact with a surface at block 260. In some embodiments, detecting
a positioning error at block 270 may be responsive to a given
distance moved by the pipette and/or surface.
In some embodiments, detecting a positioning error at block 270 may
include comparing the rate of change in pipette pressure to a
pressure error threshold. In some embodiments, detecting a
positioning error at block 270 may include determining that the
rate of change in pipette pressure is less than or equal to the
pressure error threshold. Some embodiments may include two or more
pressure error thresholds, such as, for example, 2, 3, 4, 5 or more
pressure error thresholds. In some embodiments, the pressure error
threshold may be determined using any suitable rate of aspiration
and/or rate of movement, such as those described above in regard to
the pipette pressure related threshold, the duplicate discussion
thereof may be omitted herein. Some embodiments include a pressure
error threshold that may depend on and/or be tuned based on the
pipette, the volume of fluid (i.e., liquid and/or gas) present in a
pipette tip, the rate of aspiration or dispense, and/or the fluid
type and/or properties thereof. In some embodiments, a pressure
error threshold may be empirically determined.
In some embodiments, detecting a positioning error at block 270 may
include detecting at least two consecutive data points that
indicate the positioning error has occurred. Some embodiments may
include detecting 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more
consecutive data points that indicate the positioning error has
occurred.
In some embodiments, detecting a positioning error at block 270 may
include detecting a clog in the pipette tip. In some embodiments,
detecting a positioning error at block 270 may include failing to
detect a surface. In some embodiments, failing to detect the
surface may result in the pipette tip being at a position past the
surface. In some embodiments, a clog in the pipette tip may be
caused by the pipette failing to detect the surface and the pipette
tip going into the surface (e.g., solid growth culture medium, such
as agar) and/or aspirating a portion of the surface.
Reference is now made to FIG. 8, which is a flowchart illustrating
operations of methods according to some embodiments of the present
inventive subject matter. In some embodiments, the methods may
include measuring a pipette pressure at an internal portion of a
pipette having a pipette tip attached thereto, while the pipette is
aspirating gas into the pipette tip and while the pipette and/or
surface is/are moving at block 200a. In some embodiments, measuring
the pipette pressure at an internal portion of a pipette having a
pipette tip attached thereto at block 200a includes generating a
plurality of pipette pressure values. Certain aspects of the
operation at block 200a have been described above in regard to
block 200 in FIG. 6 and duplicate discussion thereof may be omitted
herein for the purpose of discussing FIG. 8. In some embodiments,
the method may include determining a pressure difference relative
to a previously measured pipette pressure value at block 210,
estimating a rate of change in pipette pressure at block 220,
estimating a statistical variable at block 230, and/or comparing
the statistical variable to a pressure related threshold at block
240, each as described above in regard to FIG. 6.
Some embodiments include determining if the surface is in contact
and/or has been contacted with the pipette tip at block 260a.
Certain aspects of the operation at block 260a have been described
above in regard to block 260 in FIG. 6 and duplicate discussion
thereof may be omitted herein for the purpose of discussing FIG. 8.
In some embodiments, determining if the surface has been contacted
with the pipette tip at block 260a is responsive to the comparing
step at block 240. In some embodiments, determining if the surface
is in contact and/or has been contacted with the pipette tip at
block 260a includes estimating the position of the pipette tip
relative to the surface.
Referring again to FIG. 8, some embodiments include, responsive to
determining that the surface is in contact with the pipette tip at
block 260a, detecting a positioning error at block 270. Certain
aspects of the operation at block 270 have been described above in
regard to block 270 in FIG. 6 and duplicate discussion thereof may
be omitted herein for the purpose of discussing FIG. 8.
As shown in FIG. 8, some embodiments include, responsive to
determining that the surface is in contact with the pipette tip at
block 260a, stopping the movement of the pipette and/or surface and
the aspiration of gas into the pipette tip at block 280. In some
embodiments, movement of the pipette toward the surface is stopped.
Some embodiments include, responsive to stopping movement of the
pipette toward the surface, moving the pipette to a defined
position above the surface. In some embodiments, movement of the
surface toward the pipette is stopped. Some embodiments include,
responsive to stopping movement of the surface toward the pipette,
moving the surface to a defined position below the pipette.
Reference is now made to FIG. 9, which is a flowchart illustrating
operations of methods according to some embodiments of the present
inventive subject matter. In some embodiments, methods may include
aspirating a liquid into a pipette tip attached to a pipette at
block 300. The liquid may be any suitable liquid. In some
embodiments, the liquid may be a biological sample. Any suitable
volume of the liquid may be aspirated into the pipette tip. In some
embodiments, the volume of liquid may be a sufficient volume such
that at least a portion of the volume is dispensed onto the surface
of the target. Any suitable pipette tip may be releasably attached
to the pipette. In some embodiments, the pipette tip may include a
filter.
Some embodiments include positioning the pipette tip at a first
distance above a surface at block 305. The first distance may be
any suitable distance above the surface. In some embodiments, the
first distance above the surface is a known distance, which may be
determined using any devices and/or methods known to those of skill
in the art. In some embodiments, the first distance may be
determined using an optical position detector and/or an ultrasonic
position detector, as described above. In some embodiments, the
first distance may be in a range of about 0.3 mm to about 40 cm
above the surface, such as, for example, in a range of about 0.3 mm
to about 1 mm, about 0.5 mm to about 1 mm, about 0.5 mm to about 5
cm, about 1 mm to about 10 cm, about 1 mm to about 1 cm, about 2 cm
to about 10 cm, or about 10 cm to about 40 cm. In some embodiments,
the first distance may be about 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9,
1, 2, 3, 4, 5, 6, 7, 8, or 9 mm above the surface or about 1, 2, 3,
4, 5 cm or more above the surface. The first distance values
provided herein for positioning a pipette tip above a surface are
examples and are not intended to limit the scope of the invention.
For example, the first distance may be less than 0.3 mm or greater
than 40 cm.
Some embodiments include moving the pipette toward the surface
while aspirating gas into the pipette tip at block 310. The
movement of the pipette and aspiration of gas, including the rate
of movement of the pipette toward the surface and the rate of
aspiration of gas into the pipette tip, may be as described above
in reference to FIG. 6 and duplicate discussion thereof may be
omitted herein for the purpose of discussing FIG. 9. Some
embodiments include moving the liquid in the pipette tip to closer
to the proximal end of the pipette tip as the pipette moves toward
the surface and aspirates gas into the pipette tip at block 310. In
some embodiments, pipette pressure may be measured at an internal
portion of the pipette at block 320 while the pipette is moving
toward the surface and aspirating gas into the pipette tip.
In some embodiments, prior to aspirating the liquid into the
pipette tip at block 300, a first volume of gas may be aspirated
into the pipette tip. A second volume of gas may also be aspirated
into the pipette tip. In some embodiments, prior to moving the
pipette toward the surface while aspirating gas into the pipette
tip at block 310, a volume of gas may be aspirated into the pipette
tip. Accordingly, in some embodiments, the pipette tip may include,
from the proximal to distal end of the pipette tip, a first volume
of gas, the liquid, and a second volume of gas. In some
embodiments, if the second volume of gas is present, then as the
pipette moves toward the surface while aspirating gas into the
pipette tip at block 310 the second volume of gas may increase in
volume.
In some embodiments, the pipette pressure data may be collected at
block 325. The pipette pressure data may include a plurality of
pipette pressure values that may be obtained and/or generated by
measuring the pipette pressure at an internal portion of the
pipette. Some embodiments include storing the collected pipette
pressure data for a given period of time. In some embodiments, the
pipette pressure data may be stored until contact with the surface
is detected.
Some embodiments include using the pipette pressure data to detect
contact to the surface with the pipette tip at block 330. Detecting
contact to the surface at block 330 may be as described above in
reference to FIGS. 6 and 8 and duplicate discussion thereof may be
omitted herein for the purpose of discussing FIG. 9. In some
embodiments, detecting contact to a surface at block 330 may
include determining a pressure difference relative to a previously
measured pipette pressure value, estimating a statistical variable
corresponding to a rate of change in pipette pressure, comparing
the statistical variable to a pipette pressure related threshold,
and/or responsive to comparing the statistical variable to the
pipette pressure related threshold, estimating a pipette position,
each as described in reference to FIGS. 6 and 7.
Referring again to FIG. 9, some embodiments include stopping the
movement of the pipette toward the surface and the aspiration of
gas into the pipette tip at block 340. For example, movement may be
stopped responsive to detecting contact between the pipette tip and
the surface.
Some embodiments include moving the pipette to a given position
above the surface at block 350. The pipette may be moved to any
suitable position above the surface. In some embodiments, the
position above the surface may vary depending on the liquid sample
type and/or the surface type (e.g., the type of the growth culture
medium). In some embodiments, the position may be determined to
improve the chances of the sample being wicked onto the surface
and/or to reduce the risk of a false negative. In some embodiments,
the position may be such that the distal end of a pipette tip
attached to the pipette is in a range of about 0.05 mm to about 1
cm above the surface, such as, for example, in a range of about
0.05 mm to about 5 mm, about 0.1 mm to about 1 mm, about 0.1 mm to
about 0.5 mm, or about 1 mm to about 1 cm. In some embodiments, the
position may be such that the distal end of a pipette tip attached
to the pipette is about 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7,
0.8, 0.9, 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 mm above the surface.
The positions provided herein for the distal end of a pipette tip
attached to the pipette relative to a surface are examples and are
not intended to limit the scope of the invention. For example, the
position of the distal end of a pipette tip attached to the pipette
above a surface may be less than 0.05 mm or greater than 1 cm.
Reference is now made to FIG. 10, which is a flowchart illustrating
operations in systems according to some embodiments of the present
inventive subject matter. The operations in the systems may include
measuring a pipette pressure at an internal portion of a pipette at
block 400, determining a pressure difference relative to a
previously measured pipette pressure value at block 410, estimating
a rate of change in pipette pressure at block 420, estimating a
statistical variable at block 430, comparing the statistical
variable to a pipette pressure related threshold at block 440,
and/or estimating a pipette position based on the results of the
comparing at block 450. Each of these operations may be as
described above in reference to FIGS. 6 and 8 and duplicate
discussion thereof may be omitted herein for the purpose of
discussing FIG. 10.
In some embodiments, responsive to estimating a pipette position at
block 450, it may be determined if contact with a surface has been
detected at block 460. If no contact with the surface has been
detected at block 460, then the system may continue to perform one
or more of the operations described in FIG. 10 to determine if
contact with the surface is subsequently detected.
In some embodiments, if no contact with the surface has been
detected at block 460, then the system may determine if a
positioning error is detected at block 480. If no positioning error
is detected at block 480, then the system may continue to perform
one or more of the operations described in FIG. 10 to determine if
contact with the surface is subsequently detected. If a positioning
error is detected at block 480, then the system may report the
positioning error at block 485 and may stop the operations at
blocks 400, 410, 420, 430, 440, and 450.
If contact with the surface has been detected at block 460, then
the system may stop performing the operations. Some embodiments
include detecting contact with the surface at block 460 and
stopping the operations at blocks 400, 410, 420, 430, 440, and 450.
In some embodiments, responsive to detecting contact with the
surface at block 460, the system may move the pipette to a given
position above the surface at block 470.
During one or more operations described in regard to FIG. 10, the
system may be acting at one or more of the same and/or different
operations. In some embodiments, one or more operations may be
occurring at any given time.
Reference is now made to FIG. 11, which is a block diagram
illustrating a system 500 according to some embodiments of the
present inventive subject matter. The system may include a
processor 510, a memory 512, a network interface 514, a pipette
530, a pipette pressure detector 540, a pressure transducer 542,
and pressure data module 544.
The processor 510 may be configured to execute computer program
code from memory 512, described below as a computer readable
storage medium, to perform at least some of the operations and
methods described herein, and may be any conventional processor(s),
including, but not limited to the AMD Athlon.TM. 64, or Intel.RTM.
Core.TM. Duo, among others. The memory 512 may be coupled to the
processor 510 and may include computer readable program code
embodied therein that, when executed by the processor 510, may
cause the processor 510 to receive, generate, store, and/or
transmit information relating to an internal pressure in the
pipette 530 and/or the location of the pipette 530 (e.g., if the
pipette is in contact with a surface) and/or a condition of a
pipette tip (e.g., pipette tip integrity, if a pipette tip is
functioning properly, dispensing of a fluid from a pipette tip, if
a droplet is at the distal end of the pipette tip, if the pipette
tip is clogged, and/or if the pipette tip is empty).
In some embodiments, the pipette 530 may include a pipette tip,
which may be releasably attached to the pipette 530. The pipette
530 may be in electronic communication with the processor 510. The
pipette pressure detector 540 may include a pressure transducer 542
and a pressure data module 544. In some embodiments, the pressure
transducer 542 and pressure data module 544 may be integrated into
a single package. In some embodiments, the pipette pressure
detector 540 may be mounted onto the pipette 530 and/or may be
integral to the pipette 540.
The pressure transducer 542 may be in fluidic communication with
the pipette 530 and/or may be built-in to the pipette 530. In some
embodiments, the pressure transducer 542 may measure pressure
and/or vacuum profiles at an internal portion of a pipette 530. The
pressure transducer 542, pipette pressure detector 540, and/or
pipette 530 may transmit real-time pressure data to the processor
510 and/or pressure data module 544 that may be communicatively
coupled to the processor 510. The real-time pressure data may be
used to detect a surface and/or to determine a position of the
pipette 530 and/or a pipette tip attached to the pipette 530. The
pressure data module 544 may receive and/or transmit signals
corresponding to a pressure at an internal portion of the pipette
530. Some embodiments include the pressure data module 544
receiving signals from the pressure transducer 542. In some
embodiments, the pressure data module 544 may convert a signal
received from the pressure transducer 542 to a different signal
and/or signal format, such as, for example, from an analog signal
to a digital signal. In some embodiments, the pressure data module
544 may transmit signals to the processor 510. In some embodiments,
the pipette 530, pipette pressure detector 540, pressure data
module 544, and/or pressure transducer 542 may be programmable. The
pipette 530, pipette pressure detector 540, pressure data module
544, and/or pressure transducer 542 may perform and/or be utilized
in one or more operations of the methods and systems described
above.
As will be appreciated by one skilled in the art, aspects of the
present disclosure may be illustrated and described herein in any
of a number of patentable classes or context including any new and
useful process, machine, manufacture, or composition of matter, or
any new and useful improvement thereof. Accordingly, aspects of the
present disclosure may be implemented entirely hardware, entirely
software (including firmware, resident software, micro-code, etc.)
or combining software and hardware implementation that may all
generally be referred to herein as a "circuit," "module,"
"component," or "system." Furthermore, aspects of the present
disclosure may take the form of a computer program product embodied
in one or more computer readable media having computer readable
program code embodied thereon.
Any combination of one or more computer readable media may be
utilized. The computer readable media may be a computer readable
signal medium or a computer readable storage medium. A computer
readable storage medium may be, for example, but not limited to, an
electronic, magnetic, optical, electromagnetic, or semiconductor
system, apparatus, or device, or any suitable combination of the
foregoing. More specific examples (a non-exhaustive list) of the
computer readable storage medium would include the following: a
portable computer diskette, a hard disk, a random access memory
(RAM), a read-only memory (ROM), an erasable programmable read-only
memory (EPROM or Flash memory), an appropriate optical fiber with a
repeater, a portable compact disc read-only memory (CD-ROM), an
optical storage device, a magnetic storage device, or any suitable
combination of the foregoing. In the context of this document, a
computer readable storage medium may be any tangible medium that
can contain, or store a program for use by or in connection with an
instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data
signal with computer readable program code embodied therein, for
example, in baseband or as part of a carrier wave. Such a
propagated signal may take any of a variety of forms, including,
but not limited to, electro-magnetic, optical, or any suitable
combination thereof. A computer readable signal medium may be any
computer readable medium that is not a computer readable storage
medium and that can communicate, propagate, or transport a program
for use by or in connection with an instruction execution system,
apparatus, or device. Program code embodied on a computer readable
signal medium may be transmitted using any appropriate medium,
including but not limited to wireless, wireline, optical fiber
cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of
the present disclosure may be written in any combination of one or
more programming languages, including an object oriented
programming language such as Java, Scala, Smalltalk, Eiffel, JADE,
Emerald, C++, C#, VB.NET, Python or the like, conventional
procedural programming languages, such as the "C" programming
language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP,
dynamic programming languages such as Python, Ruby and Groovy, or
other programming languages. The program code may execute entirely
on the user's computer, partly on the user's computer, as a
stand-alone software package, partly on the user's computer and
partly on a remote computer or entirely on the remote computer or
server. In the latter scenario, the remote computer may be
connected to the user's computer through any type of network,
including a local area network (LAN) or a wide area network (WAN),
or the connection may be made to an external computer (for example,
through the Internet using an Internet Service Provider) or in a
cloud computing environment or offered as a service such as a
Software as a Service (SaaS).
Aspects of the present disclosure are described herein with
reference to flowchart illustrations and/or block diagrams of
methods, apparatuses (systems) and computer program products
according to embodiments of the disclosure. It will be understood
that each block of the flowchart illustrations and/or block
diagrams, and combinations of blocks in the flowchart illustrations
and/or block diagrams, can be implemented by computer program
instructions. These computer program instructions may be provided
to a processor of a general purpose computer, special purpose
computer, or other programmable data processing apparatus to
produce a machine, such that the instructions, which execute via
the processor of the computer or other programmable instruction
execution apparatus, create a mechanism for implementing the
functions/acts specified in the flowchart and/or block diagram
block or blocks.
These computer program instructions may also be stored in a
computer readable medium that when executed can direct a computer,
other programmable data processing apparatus, or other devices to
function in a particular manner, such that the instructions when
stored in the computer readable medium produce an article of
manufacture including instructions which when executed, cause a
computer to implement the function/act specified in the flowchart
and/or block diagram block or blocks. The computer program
instructions may also be loaded onto a computer, other programmable
instruction execution apparatus, or other devices to cause a series
of operational steps to be performed on the computer, other
programmable apparatuses or other devices to produce a computer
implemented process such that the instructions which execute on the
computer or other programmable apparatus provide processes for
implementing the functions/acts specified in the flowchart and/or
block diagram block or blocks.
Some embodiments provide that one or more of the programs may be
executed during a portion of execution of another one of the
programs in the corresponding process operation.
The flowchart and block diagrams in the figures illustrate the
architecture, functionality, and operation of possible
implementations of systems, methods and computer program products
according to various aspects of the present disclosure. In this
regard, each block in the flowchart or block diagrams may represent
a module, segment, or portion of code, which comprises one or more
executable instructions for implementing the specified logical
function(s). It should also be noted that, in some alternative
implementations, the functions noted in the block may occur out of
the order noted in the figures. For example, two blocks shown in
succession may, in fact, be executed substantially concurrently, or
the blocks may sometimes be executed in the reverse order,
depending upon the functionality involved. It will also be noted
that each block of the block diagrams and/or flowchart
illustration, and combinations of blocks in the block diagrams
and/or flowchart illustration, can be implemented by special
purpose hardware-based systems that perform the specified functions
or acts, or combinations of special purpose hardware and computer
instructions.
The terminology used herein is for the purpose of describing
particular aspects only and is not intended to be limiting of the
disclosure. As used herein, the singular forms "a", "an" and "the"
are intended to include the plural forms as well, unless the
context clearly indicates otherwise. It will be further understood
that the terms "comprises" and/or "comprising," when used in this
specification, specify the presence of stated features, integers,
steps, operations, elements, and/or components, but do not preclude
the presence or addition of one or more other features, integers,
steps, operations, elements, components, and/or groups thereof.
The term "about," as used herein when referring to a measurable
value, such as an amount or distance and the like, is meant to
refer to variations of up to .+-.20% of the specified value, such
as, but not limited to, .+-.10%, .+-.5%, .+-.1%, .+-.0.5%, or even
.+-.0.1% of the specified value, as well as the specified value.
For example, "about X" where X is the measurable value, is meant to
include X as well as variations of .+-.20%, .+-.10%, .+-.5%,
.+-.1%, .+-.0.5%, or even .+-.0.1% of X. A range provided herein
for a measurable value may include any other range and/or
individual value therein.
The corresponding structures, materials, acts, and equivalents of
any means or step plus function elements in the claims below are
intended to include any disclosed structure, material, or act for
performing the function in combination with other claimed elements
as specifically claimed. The description of the present disclosure
has been presented for purposes of illustration and description,
but is not intended to be exhaustive or limited to the disclosure
in the form disclosed. Many modifications and variations will be
apparent to those of ordinary skill in the art without departing
from the scope and spirit of the disclosure. The aspects of the
disclosure herein were chosen and described in order to best
explain the principles of the disclosure and the practical
application, and to enable others of ordinary skill in the art to
understand the disclosure with various modifications as are suited
to the particular use contemplated.
* * * * *
References